[Neurodegenerative changes of the retina in patients with diabetes]

To investigate the morphological and functional state of the outer and inner layers of the retina in patients with diabetes mellitus (DM) and nonproliferative diabetic retinopathy (NPDR), to determine the presence and nature of the relationships between structural and functional changes.

The study included 50 patients with subcompensated diabetes and NPDR and 40 people from the control group (healthy). All patients underwent OCT of the retina and optic nerve using RTVue-100 apparatus (Optovue, USA), as well as multifocal electroretinography (mfERG) and pattern electroretinography (PERG) on EP-1000 Multifocal device ('Tomey GmbH', Germany).

When analyzing the results of OCT in patients with NPDR, a decrease in the total thickness of the retina and the thickness of its inner layers in the fovea and parafovea regions was found in comparison with the control group (p<0.001), thinning of the retinal ganglion cell (GCS) complex with increased focal losses (FLV) of up to 1.4% (Mann-Whitney test, p=0.001). In the group of patients with diabetes, there was a statistically significant decrease in the density and amplitude of P1 mfERG in all five 'rings' (Mann-Whitney test, p<0.001), increase in implicit time in the first 3 rings, decrease in P50 and N95 amplitude, increase in implicit time of N95 PERG (p=0.001) compared to the control group.

The study revealed changes in the structure and functioning of the outer and inner layers of the retina in patients with NPDR, and established a reliable correlation between the morphological parameters (according to the OCT) and electrophysiological parameters (according to the mfERG and PERG data).